Deleting the Row of a Table Containing a BFILE

Figure 12-37 Use Case Diagram: Deleting the Row of a Table Containing a BFILE

Text description of the illustration adl12bf5.gif

See Also: "Use Case Model: External LOBs (BFILEs)" for all basic operations of External LOBs (BFILES).

Purpose

This procedure describes how to DELETE the row of a table containing a BFILE.

Usage Notes

Unlike internal persistent LOBs, the LOB value in a BFILE does not get deleted by using SQL DDL or SQL DML commands -- only the BFILE locator is deleted. Deletion of a record containing a BFILE column amounts to de-linking that record from an existing file, not deleting the physical operating system file itself. An SQL DELETE statement on a particular row deletes the BFILE locator for the particular row, thereby removing the reference to the operating system file.

Syntax

See the following syntax reference:

• SQL (Oracle9i SQL Reference), Chapter 7, "SQL Statements" -- DELETE, DROP, TRUNCATE

Scenario

The following DELETE, DROP TABLE, or TRUNCATE TABLE statements delete the row, and hence the BFILE locator that refers to Image1.gif, but leave the operating system file undeleted in the filesystem.

Examples

The following examples are provided in SQL and apply to all programmatic environments:

• "SQL: Deleting a Row from a Table"

SQL: Deleting a Row from a Table

DELETE

DELETE FROM Multimedia_tab 
   WHERE Clip_ID = 3;

DROP

DROP TABLE Multimedia_tab;
 

TRUNCATE

TRUNCATE TABLE Multimedia_tab;